Questions tagged [vector]
Mathematical vectors, operations on vectors and vectorized programming.
437
questions
0
votes
0answers
33 views
Matrix Vector multiplication [duplicate]
I have a rather simple question which surprisingly i could find the answer theres a matrix $U $ whith is $4*4$ and a vector $A$ which is $4*1$ and when I wand to multiply them by $U.A$ operator i get ...
1
vote
0answers
49 views
How to get results in terms of vector operations?
Is there a simple way to simplify an expression in terms of vector operations?
For example, when I evaluate this;
...
2
votes
1answer
34 views
Functional Opacity in VectorPlot3D
I am trying to plot a vector graph such that that vectors closest to the origin are opaque, and those furthest from the origin are transparent. I have tried using opacity with a function inside of it:
...
2
votes
2answers
95 views
Flow over the circle
I'm trying to plot a vector field over a circle, Particularly the vector field in this plot:
...
0
votes
0answers
18 views
Parametrized vector function in PDE with DSolve/NDSolve
I'm trying to solve a PDE for a parameterized function $\vec x(s, t)$ where $t \in [0, T]$ and $s \in [0, T/h]$. This PDE reads as:
$\frac{\partial \vec x}{\partial t} = \vec u (s, t)$,
$ \vec x (s,...
3
votes
2answers
105 views
Plot vectors as sums of vectors along the axes
in a phase diagram appear vectors that go in different directions. When graphing with the "streamplot" or "vectorplot" command, only the arrows appear showing how they move away from or closer to ...
0
votes
0answers
29 views
Generate vector field pointing to minimum intensity (black)
I have a black and white image and want to plot a vector field that points to the highest and nearest minimum intensity value (something like the arrows shown in the image). Similar to Gradient filter ...
2
votes
1answer
54 views
Outer (dyadic) product between vectors of the same index in two lists
I have two lists of vectors and I want to take the outer product between elements in the lists of the same index. Using either Outer or TensorProduct works for e.g. the first two indices:
...
3
votes
1answer
54 views
One-hot vectors encoding with NetEncoder
I have a text and vocabulary (text has two "the" entries):
...
0
votes
0answers
45 views
DSolve help - List encountered within
I'm reading through a physics paper (it's for the displacement of skyrmions in a 2D lattice) and just wanted a little help in visualizing an equation that is shown:
$$0=\mu \nabla^2\vec{u}+(\lambda +\...
0
votes
2answers
30 views
Piecewise vector
I need to have a vector with the length of 15000. The first 4000 elements have value 12, the next 3000 elements, that is 4001 to 7000 be 0 and the rest of it to the last be 5. I have written it with ...
3
votes
1answer
40 views
RecurrenceTable involving inputs from a vector
Directly going to the issue, my problem is how to use a RecurrenceTable when it have inputs from a vector defined previously. For instance I have:
...
0
votes
1answer
49 views
How to plot a scalar function with a vector argument? [closed]
I'm trying to take a simple dot product of two vectors and plotting it as a 3D density plot. However, I don't know how I should define the limits of the plot if the argument of the function is a ...
2
votes
1answer
115 views
Finding the tangents of the function in each mesh
I have a 2D graphic which contains a table of curves within a circular region.
...
1
vote
0answers
55 views
Mathematica Vector Integration [closed]
I am trying to symbolically integrate this function:
$$
\int\mathrm dY\exp\left[\dfrac{-(Y-Y_0)\cdot\Sigma_l^{-1}\cdot(Y-Y_0)^\top-(Y-Z\cdot A^{-1})\cdot A\cdot\Sigma_d^{-1}\cdot A^\top\cdot(Y-Z\cdot ...
0
votes
1answer
41 views
Performing a simple operation with operators [closed]
I have a map defined as
$\qquad \Phi(X) = a^2\, Tr[X] |0\rangle \langle 0| + b^2\, Tr[X] |1\rangle \langle 1| + a\,b\, Tr[\sigma_z X] |0\rangle \langle 1| + a\,b\, Tr[\sigma_z X] |1\rangle \langle ...
1
vote
1answer
120 views
Solving Laplace equation in spherical coordinates
I was trying to solve Laplace's equation for a spherical capacitor, which is not difficult by hand, just to figure out the commands so I can eventually try something more complicated. Then, I ran into ...
0
votes
0answers
65 views
Curl in Polar Coordinates
I was trying to figure out Curl in other coordinates. The Curl documentation (https://reference.wolfram.com/language/ref/Curl.html ) didn't really say how Mathematica interpreted the input.
Anyway, I ...
1
vote
2answers
109 views
How to add a vector variable to a vector value?
If we have a three dimensional vector variable:
$Assumptions = a ∈ Vectors[3];
and a three dimensional vector value for example:
...
1
vote
0answers
23 views
Text misalignment in vector graphic format export
In converting a number of old notebooks into a format for e-readers, Mathematica has some issues with vector formats. SVG export would have been ideal to use, but the exporter fails to recognize, for ...
1
vote
2answers
50 views
How to define multivariable vector funtion? [closed]
I would like to define a function of variables having two components as $u(x,y) = (f(x,y),g(x,y))$. I defined such a function as
u[x_, y_] := {f[x, y], g[x, y]}
...
1
vote
2answers
80 views
How to make a 1D VectorPlot
I am trying to use VectorPlot to produce a 1 dimensional vector plot. I Have tried using VectorPoints->{10,1} but it produces ...
4
votes
2answers
75 views
ProbabilityDistribution with variable number of dimensions
I would like to construct a ProbabilityDistribution with a variable number of dimensions. I tried to use $Assumptions = x ∈ Vectors[d, Reals] so that the variable <...
1
vote
2answers
130 views
Multivariate series for approximating implicit system
I'm trying to approximate the solution of an implicit set of equations by means of a Taylor series. I have managed to do so for a solution expressed in terms of a single independent variable, by using ...
2
votes
2answers
56 views
Normalize a vector: error [duplicate]
I have this simple example in which I am trying to write a column vector (ket vector) and then I want to normalize it. It seems that ther is something wrong, leading to an error message
"The first ...
0
votes
0answers
18 views
Multiplication of Two Vectors Not working correctly [duplicate]
I am trying to simply multiply a 1x2 vector by its transpose however Mathematica is not performing this action correctly. When I change to 2x2 matrices the multiplication works correctly however. My ...
-1
votes
1answer
75 views
How can I calculate the time-series of a vector?
I need to calculate a time-series of the vector $\|\theta(t)\|=2.2^{-t}\|v(t)\|$ where $t$ for 10 time-steps.
I was thinking of expressing the vector as a list of functions, and then the functions ...
0
votes
0answers
116 views
Why can't Nsolve find the solutions for my equations?
I have a problem using NSolve in my Mathematica code. In my Code NSolve should find a value for qw, but it won't.
The strange ...
1
vote
2answers
61 views
Find n-roots of unity and put them in vector [closed]
Assume you want to find all roots of n-unity and then you want to put them in a vector. I tried to find all the roots of unity this way:
Solve(z^n==1,z)
But now ...
7
votes
1answer
636 views
Can we turn this for loop into a more elegant Mathematica code?
I am coding stuff manipulating indirection arrays and I have some code like:
...
0
votes
0answers
55 views
Why am I getting results containing Re and Conjugate?
Using the matrix Ham4LVLReg1, I am trying to get four vectors. Initially, I got the eigenvectors, and then, I computed the eigenvectors ...
1
vote
2answers
78 views
Joining $4 \times 1$ vectors defined through functions to form a $4 \times n$ matrix
I define a $4x1 $column vector through a variable as:
Z[i_]:=List[{a[i]},{b[i]},{c[i]},{d[i]}]
I then want to make a $4\times n$ matrix by joining a specified ...
0
votes
2answers
126 views
What's wrong with this cross product of two vectors? [closed]
x = {{a},{b},{c}};
y = {{d},{e},{f}};
Cross[x,y]
Whe trying to evaluate this expression, I get the error ...
0
votes
2answers
92 views
Verifying equality $ (\vec a \times \vec b)^2 = \left| \vec a \times \vec b \right| ^2 $
I'm trying to verify the equality $ (\vec a \times \vec b)^2 = \left| \vec a \times \vec b \right| ^2 $ in Mathematica. How can I do it?
Thank you for your time.
2
votes
1answer
220 views
Plotting Vectors in Mathematica
I'm trying to plot 2D vectors in Mathematica. Built in functions don't really work for me because I want to plot vectors of matrices from the origin to the their coordinates with an arrow on their ...
3
votes
3answers
137 views
using DeleteCases to delete vectors with particular index as 0
Assume I have a set of vectors
set = {{0,1,1,0,1}, {1,0,1,1,1}, {1,1,1,1,0},{1,0,0,1,0}}.
I want to delete the vectors which have the last entry as 0. In the ...
3
votes
2answers
160 views
Animating a Vector Field
I am trying to create animations of a time dependent vector field $\vec v(t,x,y)$. The problem is that VectorPlot scales the vectors for each time $ t $ separately ...
1
vote
2answers
415 views
Orthogonal Projection of vector onto plane
I'm currently trying to learn Mathematica, and I've got some linear algebra tasks to solve with it. I've gotten quite far but now I'm stuck on this one exercise. The instructions are:
With the help ...
-1
votes
1answer
55 views
Plotting Base-vectors not working properly [closed]
I'm stuck on a issue that I can't seem to solve. After defining values for V, W and x, I'm supposed to Plot two base-vectors in the base V and with the vector x in the same picture. I'm supposed to ...
0
votes
1answer
34 views
VectorPlot not showing up after switching computers
So typed the below code into my personal computer and it worked just fine. I then moved the file to my work computer so I could look at it there, and now VectorPlot comes up blank. I am not sure if ...
1
vote
1answer
61 views
What is the best way to compute the set of vectors normal to a given one?
For 2D vectors, computing the vector orthogonal to a given $v$ is straightforwardly done using Cross, as for example shown here.
However, ...
1
vote
1answer
65 views
Calculate angle between skew vectors
I want to use Mathematica to calculate the angle between two vectors (say a and b) that don't lie in the same plane. The vectors ...
2
votes
1answer
104 views
3 dimensional vector representation with Hue color data
I am trying to represent 3-dimensional vectors in a 3-dimensional space.
In my field, there is a common color coding (color wheel) as in the picture.
For (vx,vy,vz) vectors:
(0,0,1) is white,
(0,0,-...
1
vote
1answer
49 views
Representing 3D vectors, manipulating them, and identifying symmetry operations [closed]
I am sure this is relatively straightforward, but I feel like I am missing some basic knowledge to let me find the answer.
I have a list of 3D vectors not (necessarily) originating at the origin.
...
2
votes
2answers
125 views
Problem verifying expression with 3D vectors
I am unable to verify that my vector expressions are equivalent. I want it to say true or false.
...
4
votes
2answers
116 views
Explicitly construct tensor quantities with given symmetries
I am trying to use mathematica to generate explicitely a tensor. I know multiple thing about it. Let's call it $C_{\mu\nu\lambda\sigma}$. This guy has to be symmetric in the two first indices ${\mu,\...
4
votes
1answer
153 views
Summation of Kronecker deltas should give the dimension
I have a really simple problem but I don't know how to solve it. Basically, I am doing vecor manipulation and I am summing a lot of Kronecker delta here and there. How can I teach Mathematica that for ...
2
votes
2answers
62 views
How to write a matrix of $n\times 2$ where the first column is made of only 1's?
How to write a matrix of $n\times 2$ where the first column is made of only 1's?
Suppose I have a vector x={.24,...,10}.
How can I get this
$\left(
\begin{matrix}
1 & .24 \\
1 & ...
1
vote
2answers
76 views
Evaluating a formula that uses summations and products of vectors
Could someone tell me how to find beta1?
I have the following data:
I don't know how to write beta1, and I don't find ...
0
votes
1answer
56 views
Recombining vectors after taking derivatives
I want to map two expansions order by order and to solve to get unknowns coefficient. We define $X_{\mu}= \frac{(x-y)_{\mu}}{(x-y)^2}$. The quantity I need to expand in the end is $t_{\mu\nu}= \frac{...
